1. Field of the Invention
The present invention relates to a location detection of a mobile station, and more specifically, to a method for supporting locating detection services when a mobile user accidentally turns off his mobile station.
2. Description of the Prior Art
There are many location technologies being developed and implemented into mobile stations for estimating the location of the mobile stations. These technologies include Global Positioning System (GPS), Assisted GPS (AGPS), Advanced Forward Link Trilateration (AFLT), Enhanced Observed Time Difference (EOTD), Time Difference of Arrival (TDOA), Angle of Arrival (AOA), and Enhanced Forward Link Trilateration (EFLT). Depending on the location detection technology being adopted into the mobile stations, some location detection technologies can offer a precision of up to 5 meters deviation from the actual location of the mobile station. Thus, when there is an emergency incident, a mobile phone network is capable of locating the mobile users in an efficient way.
Some of the technologies are further implemented to support emergency services such as Emergency 911 (E911) or other similar services. However, all of these features will only work as long as the mobile station is powered on. If the mobile station is powered off, the mobile station will not listen to signals emitted from the base stations and will not report anything to the base stations. Unfortunately, there are many reasons why a mobile user may intentionally or unintentionally turn off his mobile station and then forget to turn the mobile station back on later. These reasons include saving power, blocking all incoming phone calls, blocking all internal scheduled alert messages, and preventing the location of the mobile station from being traced by others. In addition, the user may simply accidentally turn off his mobile station. Regardless of the reason why the mobile station is turned off, emergency services or other authorities are not able to locate the mobile user once the mobile station is turned off. This limitation could prevent the mobile user from getting help that is urgently needed in an emergency situation.